System and Method for Providing a Feature Game

ABSTRACT

A gaming machine. A memory stores a first set of symbols including first, second, and third symbols, and a second set of replacement symbols. A symbol selector selects symbols from the set of symbols, displays the selected symbols, and selects a replacement symbol to replace a selected third symbol in response to the third symbol being selected. A value assigner randomly assigns a prize value to a selected first symbol. An outcome evaluator determines if the selected symbols include a defined number of first symbols, and triggers a feature game when a defined number of first symbols are selected. Until an end condition is met in the feature game, the symbol selector causes the display to retain a selected first symbol, remove a selected second symbol, and replace the removed second symbol with a symbol selected from the feature game set of symbols.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 15/149,060, having a filing date of May 6, 2016, which is acontinuation of U.S. patent application Ser. No. 14/823,536, having afiling date of Aug. 11, 2015, which claims priority to AustralianProvisional Patent Application No. 2014903132, having a filing date ofAug. 11, 2014. This application also claims priority to AustralianPatent Application No. 2016900462, having a filing date of Feb. 11,2016. The contents of each of the above-identified applications arehereby incorporated herein by reference in their entirety.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[Not Applicable]

MICROFICHE/COPYRIGHT REFERENCE

[Not Applicable]

FIELD OF THE INVENTION

The present invention relates to a gaming machine and a method ofgaming.

BACKGROUND OF THE INVENTION

In existing gaming machines, feature games may be triggered for playersin addition to the base game. A feature game gives players an additionalopportunity to win prizes, or the opportunity to win larger prizes, thanwould otherwise be available in the base game. Feature games can alsooffer altered game play to enhance player enjoyment.

While such gaming machines provide players with enjoyment, a need existsfor new gaming machines that are able to provide alternative featuregames, in order to maintain or increase player enjoyment.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided a gamingmachine comprising:

a symbol selector for selecting a plurality of symbols from a set ofsymbols for display during play of a game, the set of symbols includinga plurality of non-configurable symbols, a plurality of configurablesymbols, and a plurality of reveal symbols, the symbol selectorconfigured to respond to one or more reveal symbols being selected byselecting a replacement symbol, from a set of replacement symbols thatincludes a configurable symbol, to replace each reveal symbol;

a value assigner for randomly assigning one prize value of plurality ofprize values to at least each selected configurable symbol, includingany configurable symbols that replace reveal symbols; and

an outcome evaluator for monitoring play of the game, wherein a featuregame is triggered in response to a trigger event, the trigger eventcomprising a defined number of configurable symbols being selected bythe symbol selector for display;

wherein, until an end condition is met in the feature game, the symbolselector is further configured to:

1) hold any selected configurable symbols;

2) remove any selected non-configurable symbols from the display; and

3) replace any removed non-configurable symbol with another symbolselected from a feature game set of symbols that includesnon-configurable symbols and configurable symbols.

In an embodiment, said configurable symbols may each comprise at least acommon component and a variable component, said variable component beingindicative of a value of a prize that is associated with a respectiveconfigurable symbol.

In an embodiment, at least one said value of a respective prize isgenerated by selecting one of a plurality of defined multipliers that isapplied to an amount wagered.

In an embodiment, the plurality of defined multipliers are selected atrandom, a probability of selecting one of the plurality of definedmultipliers being weighted based at least in part on the amount wagered.

In an embodiment, at least one of said values of the respective prizescomprises a defined value.

In an embodiment, at least one of said values of the respective prizescomprises a progressive value which increases for each wager that isplaced on the base game by an amount proportional to said wager.

In an embodiment, the gaming machine further comprises a configurablesymbols counter for counting each of said configurable symbol that isselected for display.

In an embodiment, the game is a free game of a series of free gamestriggered in response to a trigger event in a base game, the triggerevent comprising a defined number of a defined symbol; being selected inthe base game, and when the feature game is triggered, the configurablesymbol counter is initiated to the number of selected configurablesymbols that comprise the trigger event.

In an embodiment, the configurable symbol counter is incremented eachtime a configurable symbol is selected for display in the feature game.

In an embodiment, a jackpot is awarded when the configurable symbolcounter counts a defined number of configurable symbols, the jackpotbeing a progressive prize that receives funding contributions from aplurality of other gaming machines.

In an embodiment, the gaming machine comprises a feature games counterfor counting the number of feature games to be awarded in the featuregame, wherein a defined number of feature games is initially awardedwhen the feature game is triggered.

In an embodiment, the feature game counter is reset to the definednumber of feature games initially awarded each time a configurablesymbol is selected for display in the feature game.

In an embodiment, the feature game counter is decremented each time noconfigurable symbols are selected for display in the feature game.

In an embodiment, the gaming machine further comprises an outcomeevaluator for evaluating the outcome of the game and for awarding anaccumulated prize based on said outcome, wherein the value of saidaccumulated prize is calculated by accumulating the respective prizesassociated with each of the configurable symbols selected for display.

In another aspect, the invention provides an electronic method of gamingon a gaming machine comprising the steps of:

selecting, using a symbol selector, a plurality of symbols from a set ofsymbols for display during play of a game, the set of symbols includinga plurality of non-configurable symbols, a plurality of configurablesymbols, and a plurality of reveal symbols, the selecting includingresponding to one or more reveal symbols being selected by using thesymbol selector to select a replacement symbol, from a set ofreplacement symbols that includes a configurable symbol, to replace eachreveal symbol;

randomly assigning a prize value to each selected configurable symbol,including any configurable symbols that replace reveal symbols;

monitoring, using an outcome evaluator, play of the base game, wherein afeature game is triggered in response to a trigger event, the triggerevent comprising a defined number of configurable symbols being selectedby the symbol selector for display; and

using the symbol selector until an end condition is met in the featuregame to:

1) hold the selected configurable symbols;

2) remove any selected non-configurable symbols from the display; and

3) replace any removed non-configurable symbol with another symbolselected from a feature game set of symbols that includesnon-configurable symbols and configurable symbols.

According to another aspect of the invention there is provided acomputer program code which when executed by components of a controllerof a gaming machine implements the above method.

According to another aspect of the invention there is provided atangible computer readable medium comprising the above computer programcode.

BRIEF DESCRIPTION OF THE DRAWINGS OF THE INVENTION

Features and advantages of certain embodiments of the present inventionwill become apparent from the following description of embodimentsthereof, by way of example only, with reference to the accompanyingdrawings, in which;

FIG. 1 is a block diagram of the core components of a gaming machine;

FIG. 2 is a perspective view of a standalone gaming machine;

FIG. 3 is a block diagram of the functional components of a gamingmachine;

FIG. 4 is a schematic diagram of the functional components of a memory;

FIG. 5 is a schematic diagram of a network gaming system;

FIG. 6 is a further block diagram of a gaming machine;

FIG. 7 is a flow diagram of a feature game of the gaming machine of FIG.2;

FIG. 8 is a representation of a screen of the feature game of FIG. 7;

FIGS. 9A-9C are screen shots of the feature game of FIG. 7;

FIGS. 10A and 10B are screen shots of the feature game of FIG. 7,showing one of the progressive jackpot prizes being won;

FIG. 11 is a flow diagram of a free games feature of the gaming machine;and

FIGS. 12A and 12B are screen shots of the free games feature.

The foregoing summary, as well as the following detailed description ofcertain embodiments of the present invention, will be better understoodwhen read in conjunction with the appended drawings. For the purpose ofillustrating the invention, certain embodiments are shown in thedrawings. It should be understood, however, that the present inventionis not limited to the arrangements and instrumentality shown in theattached drawings.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Referring to the drawings, there are shown example embodiments of gamingmachines having components which enable the implementation a base game,from which may be triggered a series of free games or in a spin and holdfeature game. In these embodiments, during the free games, symbols areselected from a set of symbols comprising a plurality of configurablesymbols, non-configurable symbols and reveal symbols. If reveal symbolsare selected for display, a replacement symbol is selected to replacethe reveal symbol. The replacement symbol may be a configurable symbol.In one example, the gaming machine is configured so that the spin andhold feature game is triggered when six of the configurable symbols areselected for display. The invention is not limited to triggering afeature game only when six configurable symbols are selected, however.In other embodiments, a different number of configurable symbols maytrigger the feature game.

Furthermore, each of the configurable symbols comprises a variableportion which is indicative of the value of a prize. When the featuregame is triggered, the player is guaranteed to win the accumulated valueof the prizes indicated by the variable portions of the configurablesymbols.

General Construction of Gaming Machine

The gaming machine can take a number of different forms. In a firstform, a standalone gaming machine is provided wherein all or mostcomponents required for implementing the game are present in a playeroperable gaming machine.

In a second form, a distributed architecture is provided wherein some ofthe components required for implementing the game are present in aplayer operable gaming machine and some of the components required forimplementing the game are located remotely relative to the gamingmachine. For example, a “thick client” architecture may be used whereinpart of the game is executed on a player operable gaming machine andpart of the game is executed remotely, such as by a gaming server; or a“thin client” architecture may be used wherein most of the game isexecuted remotely such as by a gaming server and a player operablegaming machine is used only to display audible and/or visible gaminginformation to the player and receive gaming inputs from the player.

However, it will be understood that other arrangements are envisaged.For example, an architecture may be provided wherein a gaming machine isnetworked to a gaming server and the respective functions of the gamingmachine and the gaming server are selectively modifiable. For example,the gaming machine may operate in standalone gaming machine mode, “thickclient” mode or “thin client” mode depending on the game being played,operating conditions, and so on. Other variations will be apparent topersons skilled in the art.

Irrespective of the form, the gaming machine 1 has several corecomponents. At the broadest level, the core components are a playerinterface 50 and a game controller 60 as illustrated in FIG. 1. Theplayer interface is arranged to enable manual interaction between aplayer and the gaming machine and for this purpose includes theinput/output components required for the player to enter instructions toplay the game and observe the game outcomes.

Components of the player interface may vary from embodiment toembodiment but will typically include a credit mechanism 52 to enable aplayer to input credits and receive payouts, one or more displays 54, agame play mechanism 56 including one or more input devices that enable aplayer to input game play instructions (e.g. to place a wager), and oneor more speakers 58.

The game controller 60 is in data communication with the playerinterface and typically includes a processor 62 that processes the gameplay instructions in accordance with game play rules and outputs gameplay outcomes to the display. Typically, the game play rules are storedas program code in a memory 64 but can also be hardwired. Herein theterm “processor” is used to refer generically to any device that canprocess game play instructions in accordance with game play rules andmay include: a microprocessor, microcontroller, programmable logicdevice or other computational device, a general purpose computer (e.g. aPC) or a server. That is a processor may be provided by any suitablelogic circuitry for receiving inputs, processing them in accordance withinstructions stored in memory and generating outputs (for example on thedisplay). Such processors are sometimes also referred to as centralprocessing units (CPUs). Most processors are general purpose units,however, it is also know to provide a specific purpose processor usingan application specific integrated circuit (ASIC) or a fieldprogrammable gate array (FPGA).

A gaming machine in the form of a standalone gaming machine 10 isillustrated in FIG. 2. The gaming machine 10 includes a console 12having a display 14 on which are displayed representations of a game 16that can be played by a player. A mid-trim 20 of the gaming machine 10houses a bank of buttons 22 for enabling a player to interact with thegaming machine, in particular during game play. The mid-trim 20 alsohouses a credit input mechanism 24 which in this example includes a coininput chute 24A and a bill collector 24B. Other credit input mechanismsmay also be employed, for example, a card reader for reading a smartcard, debit card or credit card. Other gaming machines may configure forticket in such that they have a ticket reader for reading tickets havinga value and crediting the player based on the face value of the ticker.A player marketing module (not shown) having a reading device may alsobe provided for the purpose of reading a player tracking device, forexample as part of a loyalty program. The player tracking device may bein the form of a card, flash drive or any other portable storage mediumcapable of being read by the reading device. In some embodiments, theplayer marketing module may provide an additional credit mechanism,either by transferring credits to the gaming machine from credits storedon the player tracking device or by transferring credits from a playeraccount in data communication with the player marketing module.

A top box 26 may carry artwork 28, including for example pay tables anddetails of bonus awards and other information or images relating to thegame. Further artwork and/or information may be provided on a frontpanel 29 of the console 12. A coin tray 30 is mounted beneath the frontpanel 29 for dispensing cash payouts from the gaming machine 10.

The display 14 shown in FIG. 2 is in the form of a video display unit,particularly a liquid crystal display. Alternatively, the display 14 maybe an OLED, plasma screen, any other suitable video display unit. Thetop box 26 may also include a display, for example a video display unit,which may be of the same type as the display 14, or of a different type.

FIG. 3 shows a block diagram of operative components of a typical gamingmachine which may be the same as or different to the gaming machine ofFIG. 2.

The gaming machine 10 includes a game controller 101 having a processor102 mounted on a circuit board. Instructions and data to controloperation of the processor 102 are stored in a memory 103, which is indata communication with the processor 102. Typically, the gaming machine10 will include both volatile and non-volatile memory and more than oneof each type of memory, with such memories being collectivelyrepresented by the memory 103.

The gaming machine has hardware meters 104 for purposes includingensuring regulatory compliance and monitoring player credit, aninput/output (I/O) interface 105 for communicating with peripheraldevices of the gaming machine 100. The input/output interface 105 and/orthe peripheral devices may be intelligent devices with their own memoryfor storing associated instructions and data for use with theinput/output interface or the peripheral devices. A random numbergenerator module 113 generates random numbers for use by the processor102. Persons skilled in the art will appreciate that the reference torandom numbers includes pseudo-random numbers.

In the example shown in FIG. 3, a player interface 120 includesperipheral devices that communicate with the game controller 101including one or more displays 106, a touch screen and/or buttons 107(which provide a game play mechanism), a card and/or ticket reader 108,a printer 109, a bill acceptor and/or coin input mechanism 110 and acoin output mechanism 111. Additional hardware may be included as partof the gaming machine 100, or hardware may be omitted as required forthe specific implementation. For example, while buttons or touch screensare typically used in gaming machines to allow a player to place a wagerand initiate a play of a game any input device that enables the playerto input game play instructions may be used. For example, in some gamingmachines a mechanical handle is used to initiate a play of the game.Persons skilled in the art will also appreciate that a touch screen canbe used to emulate other input devices, for example, a touch screen candisplay virtual buttons which a player can “press” by touching thescreen where they are displayed.

In addition, the gaming machine 100 may include a communicationsinterface, for example a network card 112. The network card may, forexample, send status information, accounting information or otherinformation to a bonus controller, central controller, server ordatabase and receive data or commands from the bonus controller, centralcontroller, server or database. In embodiments employing a playermarketing module, communications over a network may be via playermarketing module—i.e. the player marketing module may be in datacommunication with one or more of the above devices and communicate withit on behalf of the gaming machine.

FIG. 4 shows a block diagram of the main components of an exemplarymemory 103. The memory 103 includes RAM 103A, EPROM 103B and a massstorage device 103C. The RAM 103A typically temporarily holds programfiles for execution by the processor 102 and related data. The EPROM103B may be a boot ROM device and/or may contain some system or gamerelated code. The mass storage device 103C is typically used to storegame programs, the integrity of which may be verified and/orauthenticated by the processor 102 using protected code from the EPROM103B or elsewhere.

It is also possible for the operative components of the gaming machine100 to be distributed, for example input/output devices106,107,108,109,110,111 to be provided remotely from the game controller101.

FIG. 5 shows a gaming system 200 in accordance with an alternativeembodiment. The gaming system 200 includes a network 201, which forexample may be an Ethernet network. Gaming machines 202, shown arrangedin three banks 203 of two gaming machines 202 in FIG. 5 are connected tothe network 201. The gaming machines 202 provide a player operableinterface and may be the same as the gaming machines 10,100 shown inFIGS. 2 and 3, or may have simplified functionality depending on therequirements for implementing game play. While banks 203 of two gamingmachines are illustrated in FIG. 5, banks of one, three or more gamingmachines are also envisaged.

One or more displays 204 may also be connected to the network 201. Forexample, the displays 204 may be associated with one or more banks 203of gaming machines. The displays 204 may be used to displayrepresentations associated with game play on the gaming machines 202,and/or used to display other representations, for example promotional orinformational material.

In a thick client embodiment, game server 205 implements part of thegame played by a player using a gaming machine 202 and the gamingmachine 202 implements part of the game. With this embodiment, as boththe game server and the gaming device implement part of the game, theycollectively provide a game controller. A database management server 206may manage storage of game programs and associated data for downloadingor access by the gaming devices 202 in a database 206A. Typically, ifthe gaming system enables players to participate in a Jackpot game, aJackpot server 207 will be provided to perform accounting functions forthe Jackpot game. A loyalty program server 212 may also be provided.

In a thin client embodiment, game server 205 implements most or all ofthe game played by a player using a gaming machine 202 and the gamingmachine 202 essentially provides only the player interface. With thisembodiment, the game server 205 provides the game controller. The gamingmachine will receive player instructions, pass these to the game serverwhich will process them and return game play outcomes to the gamingmachine for display. In a thin client embodiment, the gaming machinescould be computer terminals, e.g. PCs running software that provides aplayer interface operable using standard computer input and outputcomponents. Other client/server configurations are possible, and furtherdetails of a client/server architecture can be found in WO 2006/052213and PCT/SE2006/000559, the disclosures of which are incorporated hereinby reference.

Servers are also typically provided to assist in the administration ofthe gaming network 200, including for example a gaming floor managementserver 208, and a licensing server 209 to monitor the use of licensesrelating to particular games. An administrator terminal 210 is providedto allow an administrator to run the network 201 and the devicesconnected to the network.

The gaming system 200 may communicate with other gaming systems, otherlocal networks, for example a corporate network, and/or a wide areanetwork such as the Internet, for example through a firewall 211.

Persons skilled in the art will appreciate that in accordance with knowntechniques, functionality at the server side of the network may bedistributed over a plurality of different computers. For example,elements may be run as a single “engine” on one server or a separateserver may be provided. For example, the game server 205 could run arandom generator engine. Alternatively, a separate random numbergenerator server could be provided. Further, persons skilled in the artwill appreciate that a plurality of game servers could be provided torun different games or a single game server may run a plurality ofdifferent games as required by the terminals.

Further Detail of Gaming Machine

The player operates the game play mechanism 56 to specify a wager andhence the win entitlement which will be evaluated for this play of thegame and initiates a play of the game. Persons skilled in the art willappreciate that a player's win entitlement will vary from game to gamedependent on player selections. In most spinning reel games, it istypical for the player's entitlement to be affected by the amount theywager and selections they make (i.e. the nature of the wager). Forexample, a player's win entitlement may be based on how many lines theyplay in each game—e.g. a minimum of one line up to the maximum number oflines allowed by the game (noting that not all permutations of win linesmay be available for selection) and how much they wager per line. Suchwin lines are typically formed by a combination of symbol displaypositions, one from each reel, the symbol display positions beinglocated relative to one another such that they form a line.

In many games, the player's win entitlement is not strictly limited tothe lines they have selected, for example, “scatter” pays are awardedindependently of a player's selection of paylines and are an inherentpart of the win entitlement.

Persons skilled in the art will appreciate that in other embodiments,the player may obtain a win entitlement by selecting a number of reelsto play and an amount to wager per reel. Such games are marketed underthe trade name “Reel Power” by Aristocrat Leisure Industries Pty Ltd.The selection of the reel means that each displayed symbol of the reelcan be substituted for a symbol at one or more designated displaypositions. In other words, all symbols displayed at symbol displaypositions corresponding to a selected reel can be used to form symbolcombinations with symbols displayed at a designated, symbol displaypositions of the other reels. For example, if there are five reels andthree symbol display positions for each reel such that the symboldisplay positions comprise three rows of five symbol display positions,the symbols displayed in the centre row are used for non-selected reels.As a result, the total number of ways to win is determined bymultiplying the number of active display positions of each reel, theactive display positions being all display positions of each selectedreel and the designated display position of the non-selected reels. As aresult for five reels and fifteen display positions there are 243 waysto win.

In FIG. 6, the processor 62 of game controller 60 of gaming machine 1 isshown implementing a number of modules based on game program code 641stored in memory 64. Persons skilled in the art will appreciate thatvarious of the modules could be implemented in some other way, forexample by a dedicated circuit.

These modules include the outcome generator 622 which operates inresponse to the player's operation of game play mechanism 56 to place awager and initiate a play of the game and generates a game outcome whichwill then be evaluated by outcome evaluator 623. The first part offorming the game outcome is for a symbol selector 622A to select symbolsfrom a set of symbols specified by symbol data 642 using random numbergenerator 621. The selected symbols are advised to the displaycontroller 625 which causes them to be displayed as a symbol display ondisplay 54 at a set of display positions.

In the embodiment described below, the display positions of the symboldisplay are arranged in a rectangular matrix comprising a plurality ofcolumns and a plurality of rows. However, in other arrangements as knownin the gaming industry could be employed in embodiments of theinvention. For example, in some arrangements there are more symbols insome columns than other, such as 3-4-3-4-3 arrangement of seventeendisplay positions corresponding to respective ones of five reels. Insuch arrangements, the columns of four symbols can be arranged so thatthey are off-set or staggered relative to the columns having two symbolsso that the middle two symbols in the columns of four symbols shareboundaries with two symbols of each neighbouring reel.

FIG. 7 shows a flow diagram of one embodiment, in which a feature gamemay be triggered from play of the base game at step 702. In thisembodiment, the base game comprises using symbol selector 622A to selecta plurality of symbols from a set of symbols to display at therespective display positions arranged on display 54, at step 704. Theset of symbols, which are stored as symbol data 642 in memory 64,comprises a plurality of configurable symbols and non-configurablesymbols.

In an embodiment, the configurable symbols each comprise at least acommon component and at least a variable component. The variablecomponent is indicative of a value of a prize that is associated witheach of the configurable symbols. An example of a configurable symbol isshown in FIGS. 9A-9C, in the form of a pearl symbol. The commoncomponent is the pearl itself 902, while the variable component is theindicia 904 overlaying pearl 902. In this case, indicia 902 are numeralsdirectly indicative of the value of the prize. In other embodiments,such as shown in FIG. 10A-10B, the indicia indirectly indicate the valueof the prize, such as “major” indicia 1002, “minor” indicia 1004 or“mini” indicia 1006. It will be appreciated that the indicia can also bein other forms, which may also be indicative of a prize. For example,the car icon indicates that the player has the opportunity to, or has,won a car. In some embodiments, the indicia may indicate only a portionof a prize. Continuing with the car example, the car icon may be splitinto four portions, each portion being assigned to a differentconfigurable symbol. In such embodiments, all four portions of the caricon are required to be selected for display in order for the car prizeto be won.

In one embodiment, at least one value of the respective prizes isgenerated by randomly selecting one of a plurality of definedmultipliers that is applied to an amount wagered on the base game fromwhich the feature is game triggered. This is accomplished at step 706using value assigner 622C, which selects the defined multipliers fromvalue data 644 using a value obtained from the random number generator(RNG) 621, applies the multiplier to the initial wager to obtain a prizevalue and assigns the prize value to each of the configurable symbolsselected by symbol selector 622A. The plurality of defined multipliersin this embodiment are selected at random according to a weightedprobability based at least in part on the amount wagered on the basegame. That is, for at least each configurable symbol which will bedisplayed, the value assigner 622C obtains a value from RNG 621 and usesthis to determine from the weighted table which value to assign. In anembodiment, the assignment of values to the configurable symbols isperformed by the value assigner 622C after the symbols have beenselected and the game controller knows they will be displayed but beforethey are displayed on the display. In another embodiment, the assignmentoccurs after the symbols have been displayed on display 54. In anembodiment, values are assigned to all configurable symbols irrespectiveof whether they will be displayed.

In this or other embodiments, at least one value of the respectiveprizes may comprise a defined value and/or a jackpot. As used herein,the term “jackpot”, as opposed to “prize”, refers to a progressive prizewhich accumulates over multiple plays of the base game and/or thefeature game. As will be appreciated, the jackpot may be funded from avariety of sources including from only the gaming machine 10 itself, orfrom a plurality of gaming machines 202—a so-called “link”. Furthermore,the jackpot may be triggered by any means known in the art, such as byusing a mystery trigger or by using the Hyperlink™ system developed bythe applicant.

In another embodiment, the variable prizes may be randomly selectedunder the control of value assigner 622C from a set of available prizes.Specific prizes may be weighted so as to control the probability ofcertain prizes occurring. In some embodiments, there may be a pluralityof sets of prizes and the value assigner 622C may be configured tochoose the set of prizes from which values will be randomly selected onthe basis of a player's wager in the base game.

Returning to FIG. 7, at step 710, outcome evaluator 623 monitors play ofthe base game and determines whether a trigger event has occurred. Inthis embodiment, a trigger event occurs when six configurable symbolsappear on display 54. If a trigger event has not occurred, play of thebase game continues and control reverts to step 702, once any awards arepaid at step 708. However, if a trigger event does occur, the featuregame initiates by first holding the configurable symbols in theirrespective display positions 824, at step 711. Outcome generator 622causes the feature game to be displayed on display 54 by retrievingsymbol data 642 from memory 64 and passing the data to displaycontroller 625 which controls display 54 to display the feature game. Inother embodiments, more than or less than six symbols will be requiredto trigger the feature game, or the feature game will be modified in away that is proportional to the number of configurable symbols that aredisplayed to trigger the feature game. For example, the average or totalprize achievable in the feature game may be increased in proportion tothe number of configurable symbols appearing.

When the feature game starts, the configurable symbol counter 810 ofFIG. 8 is set to the number of configurable symbols that are held onreels 814-822, at step 712. In some embodiments, the configurable symbolcounter 810 is an electronic counter in which the count is displayed inArabic numerals In the display. In the preferred embodiment, this isalso the number of configurable symbols which originally triggered thefeature game. That is, in this embodiment, the configurable symbolcounter 810 is initially set to 6, as six configurable symbols arerequired to trigger the feature game. Alternatively, if sevenconfigurable symbols are selected for display, but only six are requiredfor triggering the feature game, the configurable symbol counter 810 maybe initially set to seven.

Once configurable symbol counter 810 is set, control moves to step 714which sets feature game counter 812 to the defined number of featuregames. In an embodiment, the preferred number of feature games is three,so counter 812 is set to 3. In other embodiments, the number of featuregames may be more than or less than three, or may be derived by the gamecontroller from the number of configurable symbols that appear. Forexample, an additional feature game may be offered for each configurablesymbol that appears in addition to a defined minimum (for example, six)required to trigger the feature game.

Then, similar to the base game, the symbol selector 622A selects symbolsfrom symbol data 642 to be displayed in the other display positions 824not already displaying a configurable symbol, via display controller625, at step 716. Note that in this embodiment, symbols in the featuregame are selected from the full set of symbols defined by symbol data642, including any configurable symbols. In other embodiments, thesymbols may be selected from a reduced set of symbols taking intoaccount of the configurable symbols already held. In an alternativeembodiment, the symbols may be selected from an increased set ofsymbols. For example, symbols may be purchased or otherwise awarded foraddition to the reel strip prior to the initiating the feature game. Ifone or more configurable symbols are selected, value assigner 622Cassigns randomly selected values to each configurable symbol.

Outcome evaluator 623 then monitors play of the feature game todetermine whether a configurable symbol is selected and displayed atstep 718. If a configurable symbol is not displayed, feature gamecounter 812 is decremented by a defined amount at step 720. In thepreferred embodiment, feature game counter 812 is only decremented byone, but of course the counter may be decremented by any number as isknown in the art.

If there are a number of feature games remaining as determined bycontroller 60 at step 722, control returns to step 716 to continue thefeature game. On the other hand, once the number of feature games isdepleted, that is, when the feature game counter 812 reaches zero, anend condition is met, the feature game ends and control returns to step702 after any prizes are paid at step 728. In one embodiment, theaccumulated value of all the individual prizes as indicated by thevariable components of the collected configurable symbol is paid at step728.

Returning to step 718, if outcome evaluator 623 determines that at leastone configurable symbol is displayed on reels 814-822, then that symbolis held on the reel, at step 723, and the configurable symbol counter810 is incremented at step 724. Outcome evaluator 623 then checkswhether a defined number of configurable symbols has been displayed onreels 814-822 at step 726 and, if the defined number has been reached, ajackpot is paid at step 728.

The defined number of configurable symbols required to trigger a jackpotin this embodiment is fifteen. That is, for this embodiment in which agame is implemented using a 5×3 matrix, configurable symbols must beselected and displayed in all the matrix positions of reels 814-822. Inother embodiments, the defined number may be more than or less thanfifteen. For example, in a 3-4-3-4-3 matrix configuration discussed asdiscussed above, the number of configurable symbols required to fill allmatrix positions would be 17. In yet other embodiments, not all of thematrix positions need necessarily be filled, and the number ofconfigurable symbols required may be determined randomly.

While in the above embodiments, an end condition is that the featuregame ends when the Grand jackpot 802 is triggered at step 726. In otherembodiments, the feature game does not necessarily end at this point. Insuch embodiments, one or more of reels 814-822 are configured to expandand display additional configurable or non-configurable symbols whencounter 810 reaches the defined number. For example, a game implementedusing a 5×3 matrix may expand to a 3-4-3-4-3 configuration. In suchembodiments, a prize in addition to the Grand jackpot 802 is paid ifconfigurable symbols are also selected for display in those additionalpositions.

Alternatively, if outcome evaluator 623 determines that the definednumber of configurable symbols has not been reached at step 726, thefeature game continues. In the embodiment of FIG. 7, each time aconfigurable symbol is displayed and the jackpot is not won, featuregame counter 812 is reset to the default position by returning controlto step 714, which in this embodiment is three as noted above.Therefore, the number of feature games awarded by the outcome evaluator623 is indefinite and is not determined by a defined limit.

In this or other embodiments, if no configurable symbols appear on reels814-822 in any of the feature games initially awarded, feature gamescounter 812 is reset. Such embodiments ensure the player is guaranteedto win a prize over and above the prize payable for triggering thefeature game.

In the above embodiments, the jackpot paid in response to counter 810reaching the defined threshold is Grand prize 802. The grand prize inthis embodiment is a linked jackpot which receives contributions from aplurality of linked gaming machines and incremented based on theturnover of the linked machines. In some embodiments, a lower thresholdof configurable symbols may be required for Major prize 804, Minor prize806 or mini prize 808 to be won. Alternatively or additionally, as bestshown in FIGS. 10A and 10B, Major, Minor and Mini prizes may be paid byassignment of those prizes to one of the configurable symbols, such as“major” indicia 1002, “minor” indicia 1004 or “mini” indicia 1006.

Note that in some embodiments, one or all of the Grand 802, Major 804,Minor 806 and Mini 808 prizes may all be implemented as jackpots, asfixed bonus amounts that do not increment or as a mixture of both. Inthe embodiment of FIGS. 9A to 10B, as noted above, Grand prize 802 isimplemented as a linked progressive jackpot, while Major prize 804 isimplemented as a standalone progressive (SAP) jackpot which only takescontributions from the gaming machine itself, incrementing the jackpotas a function of turnover. Minor 806 and Mini 808 prizes are implementedas fixed bonus amounts in proportion to the initial bet wagered. In someembodiments, Grand 802 prize may also be implemented as a SAP, or theMajor 804 prize may also be implemented as a link.

This embodiment implements Grand 802 and Major 804 prizes as jackpotsand, while both may be awarded simultaneously, neither can be awardedmore than once in the same feature game. However, in other embodiments,either jackpot may be won multiple times within the same feature game.In such embodiments, players are awarded a seed value of the jackpot forsubsequent triggers of that same jackpot.

As embodiments of the feature game described above automatically adjustawards based on turnover and proportionality to the initial wager, thisinvention is particularly suited to variable denomination games.Therefore, in some embodiments, controller 60 allows player selection ofthe minimum bet denomination. For example, before play of the game,controller 60 causes display controller 625 to output a message ondisplay 54 requesting the player to select a minimum bet denomination.The player makes a selection through the game play mechanism 56 inresponse to which controller 60 adjusts the amount contributed to Grand802 and Major 804 jackpot prizes and the magnitude of Minor 806 and Mini808 bonus awards. Controller 60 also adjusts the weightings of thevalues in value data 644 from which value assigner 622C may assign tothe configurable symbols. In one embodiment, there are fourdenominations available for selection, 1 c, 2 c, 5 c and 10 c. Thoseskilled in the art would appreciate that the denominations are notlimited to four, but can include any suitable amount in any givencurrency. Note also that in this embodiment, while the selecteddenomination affects the magnitude of the Minor 806 and Mini 808 fixedbonus prizes offered, it does not affect the magnitude of the Grand 802and Major 804 jackpots—only the contributions funding the amount.

Referring again to FIG. 7, it will be apparent that the flow chartincludes a free game process at step 707. Like the spin and hold featuregame, the free game process is a second game comprised of a plurality ofgames which occurs only periodically if a trigger condition is met.

The free game process 707 is detailed in FIG. 11. In an embodiment, thefree game process 707 involves the step 1105 of determining whether thefree game process is triggered. In an embodiment, the trigger is adefined number of a defined symbol being selected for display by thesymbol selector. For example, three or more scatter symbols appearinganywhere in the display positions. If the free game process is nottriggered, the process flow continues to step 710 (FIG. 7).

If the free game process is triggered, then at step 1110 a free gamecounter is set to a defined number of free games for play. For example,eight free games may be the defined number of games.

The free game process 707 then involves selecting symbols from a freegame symbol set, at step 1115. In one example, the free game symbol setcomprises a set of reels formed from the set of symbols used in the basegame and a plurality of reveal symbols. The free game symbol set isstored in symbol data 642 (FIG. 6) together with the set of symbols tobe used during the base game and the feature game.

It will be appreciated that in other embodiments, the symbols of thefree game symbol set could be significantly different to the symbolsused in the base game. For example, a reveal symbol could replace asymbol used in the base game as another example, no configurable symbolsare in the free game symbol set. It will be appreciated that thepreferred free game symbol set includes a mixture of configurable andnon-configurable symbols as in the base game symbol set.

After the symbols have been selected at step 1115, the free game counteris decremented by one at step 1120. At step 1125, the free game process707 involves determining whether the selected symbols includeconfigurable symbols, and if so, the values are assigned to eachconfigurable symbol at step 1130. Again, any of the options forassigning values to each configurable symbol described above can beused. In an embodiment, the free game process 707 for assigning valuesis the same as that used in the base game and the feature game.

As indicated above, the set of free game symbols includes a plurality ofreveal symbols. A determination is made at step 1135 whether theselected symbols include one or more reveal symbols. If so, a process toselect a replacement symbol from a set of replacement symbols isinitiated at step 1140. In an example, the replacement symbol setcomprises the full set of free game symbols. The set of replacementsymbols will not include a defined symbol for the trigger condition (forexample, a scatter symbol) so that the selection of a replacement symbolfor the reveal symbol cannot lead to a retrigger of the free gameprocess. In other embodiments, the replacement symbol set could be areduced set of symbols, for example symbols that are in higher valuewinning combinations defined in a pay table. In other embodiments, noconfigurable symbols are in the replacement symbol set. Accordingly, inthe embodiment, the set of replacement symbols includes at least oneconfigurable symbol. Accordingly, one possible result of selection ofthe replacement symbol is for the configurable symbol to be selected.Irrespective of what symbol is selected, this symbol will replace all ofthe reveal symbols. Thus, the reveal symbol is termed a reveal symbolbecause it will reveal to the player the act of replacing with thereplacement symbol. In an embodiment, at least one weighted table isused to control the selection of the replacement symbol. In an example,two weighted tables are used. A first table is used when at least onedisplay position is not occupied by a reveal symbol, and a second tableis used if all display positions are occupied by a reveal symbol. Thesecond table is configured to change on per bet basis to ensure thechance of a configurable symbol being revealed is proportional to thetotal credits bet, thereby making the probability of winning the GrandJackpot linear. It will be apparent why the gaming machine is configuredto operate in this manner from the following description.

At step 1145, it is determined whether the replacement symbol is aconfigurable symbol. If the replacement symbol is a configurable symbol,then at step 1150, a value is assigned to each configurable symbol. Eventhough a configurable symbol is chosen to replace each reveal symbol,the values assigned to the respective configurable symbols can bedifferent. In this respect, referring to FIG. 12 it will be apparentthat there is shown an exemplary screenshot in FIG. 12A where the sixthfree game in a series of free games is being carried out as indicated infree games counter 1210.

It will be apparent in FIG. 12A that a display shows the gaming machineafter a set of symbols have been selected for the free game where twoconfigurable symbols 1226, 1227, have been selected but before thereplacement symbol selected for the reveal symbols 1231, 1232, 1233,1234, 1235, has been displayed. The configurable symbols 1226, 1227 arein the form of coin symbols having text thereon which show theirconfigure values, in this example values of 1000 credits (configurablesymbol 1226) and 250 credits (configurable symbol 1227). Five revealsymbols in the form of “Wanted Poster” symbols 1231 to 1235 have alsobeen selected.

FIG. 12B shows the same free game of FIG. 12A after a replacement symbolhas been selected for each reveal symbol. It will be apparent that thereplacement symbol that has been selected is a configurable symbol andvalues have been assigned to each of the configurable symbol by thevalue assigner. Specifically, a major jackpot prize value has beenassigned to configurable symbol 1221, a value of 150 credits has beenassigned to configurable symbol 1222, a prize of 250 credits has beenassigned to configurable symbol 1223, a prize of a mini bonus has beenassigned to configurable symbol 1224, and a prize of 50 credits has beenassigned to configurable symbol 1225.

Returning now to FIG. 11, it is determined at step 1160 whether the spinand hold feature game is triggered from the symbols selected in the freegame using the same trigger condition used in the base game in respectof triggering the feature game, as described above. If so, the free gameprocess 707 continues to steps 711 with all of the configurable symbolsheld in the manner described above in relation to FIG. 7. That is, thegaming machine operates such that the feature game described above iscarried out as a result of the trigger condition being met within thefree game process.

Otherwise, the process continues to awarding any prize at step 1165, andthen at step 1170 determines whether a retrigger of the free gameprocess is included within the set of symbols that were selected. In anembodiment, a retrigger is achieved by the same number of definedsymbols appearing at scatter positions as was required to initiallytrigger the free game process. In an embodiment, the retrigger can beallowed on only the first occasion where it occurs. In an example, eightfurther free games are added to the free game counter at step 1175 if aretrigger occurs.

Once the feature game ends at step 722, the feature award is paid atstep 728. Then at step 730, it is determined whether the feature gamewas triggered from the free game process 707 (of FIG. 11). If thefeature was triggered from the free game process 707 (of FIG. 11), thenat step 732 (of FIG. 7), the process flow returns to step 1180 (of FIG.11) where it is determined if the free game process has ended. If thefree game process has ended, the process flow continues to step 710where it is determined whether the free game process terminated with afeature trigger. If the free game process terminated with a featuretrigger, the feature game is played at step 711, and then the processflow is returned to base game play at step 730. As will suggest itself,step 1180 (in another embodiment) may flow directly back to the basegame at step 702.

If at step 1180, the free game counter is greater than zero the processcontinues to step 1115 and a further free game is carried out byselecting further symbols and carrying out the subsequent stepsdescribed above.

It will be apparent from the above description that an advantage of thefree game process 707 described in FIG. 11 is that the gaming machine isconstructed so as to provide a second opportunity for the player totrigger the feature game by means of the use of the free game process.As such, the gaming machine is constructed such that the free gameseries is integrated with the hold and spin feature game. Further, thisis done so in a manner which ensures that once the feature game istriggered, the player has at least a guaranteed prize from the values ofthe configurable symbols. Accordingly, the embodiments provide asignificantly improved method of operating a gaming machine.

Examples

More specific examples of embodiments of the invention are now describedwith reference to FIGS. 9A-10B. In general, as shown in these Figures,the game has a traditional 3×5 grid layout, and is referred to in theexamples below as the “Hold & Spin” feature.

Referring to FIG. 9A, the Hold & Spin feature is triggered when six 6pearl symbols 902 are selected for display. When triggered, pearls 902are held in their respective display positions, being all of column 1,column 2 rows 1 and 2 and column 5 row 1, and the controller 60 waitsfor a player instruction to initiate the game through game playmechanism 56. In some embodiments, controller 60 will wait indefinitelywhile in other embodiments, controller 60 will wait for a defined periodof time before automatically initiating the game.

At this point, counter 810 is set to 6, and the player is guaranteed towin the accumulated value as indicated by the variable components 904 ofthe six pearls 902. That is, even before play of Hold & Spin starts, theplayer has won 4,300 credits in the embodiment of FIG. 9A.

Moving on to FIG. 9B, the player has spun an additional 4 pearls 902.Accordingly, counter 810 is incremented from 6 to 10 and feature gamescounter 812 is reset to default, which is 3 feature games in thisembodiment. As compared to FIG. 9A, the additional pearls 902 areselected for display at display positions C2R3, C3R1, C4R3 and C5R2, andare also held at those positions for the subsequent games.

Over the remaining feature games, the player spins only an additionalone pearl 902, displayed at C4R1, as shown in FIG. 9C. Accordingly, thefeature games end, and the player wins the accumulated value of thevalues indicated on pearls 902. In this case, the total award is the4,300 credits for the six pearls 902 that originally triggered the Hold& Spin game, plus the additional 5 pearls 902 selected during play ofthe Hold & Spin game—5,800 credits. In this embodiment, the accumulatedaward is totalled at the end of the Hold & Spin game and firsttransferred to the win meter 908 before being transferred to the creditmeter 910 by the controller 60. Meter data 648 is adjusted accordinglybefore the next game can be initiated at step 702. In alternativeembodiments, the accumulated award may bypass the win meter and becredited directly to the credit meter.

FIGS. 10A and 10B are examples showing the jackpots being own. In FIG.10A, value assigner 622C has assigned “Major” indicia 1002 to pearl 902,which has been selected for display at C4R1. This triggers Major prize804 which, in one embodiment, is paid directly into credit meter 910rather than first into win meter 908. That is, jackpot wins are paidimmediately when they are won rather than being accumulated at the endof the Hold & Spin game as per the other prizes described above. Thus inthe FIG. 10A embodiment, Major jackpot 804 is paid when the associatedpearl 902 is selected, while the remaining 4,000 credits will beaccumulated and paid at the completion of the feature game, in additionto any new pearls 902 that are selected and displayed in the remainingfeature games. In alternative embodiments, the Major jackpot may beaccumulated at the end of the feature game along with the other 4,000credits, and the accumulated total may be paid first into win meter 908or directly into credit meter 910.

FIG. 10B shows Grand jackpot 802 being triggered, as 15 pearls 902 havebeen selected for display in the matrix by the end of the feature game.Again, the Grand 802 jackpot is first accounted for and paid directlyinto credit meter 910, and the remaining prizes indicated by indicia 904on pearls 902 are then accumulated and paid into win meter 908 beforebeing transferred to credit meter 910. Therefore, in this FIG. 10Bembodiment, the total winnings is made up of the initial Grand jackpot802, plus 63,000 credits indicated by indicia 904 and Minor 806 and Mini808 prizes indicated by “Minor” indicia 1004 and “Mini” indicia 1006.Again, in alternative embodiments, the Grand jackpot may be accumulatedat the end of the feature game along with the other 63,000 credits,Minor prize 806 and Mini prize 808, and the accumulated total may bepaid first into win meter 908 or directly into credit meter 910.

In another example, the configurable symbols may only be provided duringpart of the game, such as a feature game.

In another example, after a feature game is triggered, the gamecontroller initiates a feature game using different reels to those usedin the base game. In one example, in the feature game, individual reelsare associated with each of the symbol display positions. That is, ifthere are fifteen symbol display positions, fifteen reels are availablefor use depending upon which of the display positions are occupied bythe configurable symbols that caused the feature game to trigger. Eachof the reels comprises a mixture of non-configurable symbols andconfigurable symbols. In the first feature game, the symbol selectordetermines stopping positions for all of the reels not occupied by aconfigurable symbol. If any of the reels are stopped with a configurablesymbol in place, that configurable symbol is held in position byholding/locking the reel (i.e. not spinning the reels in a subsequentfeature game). That is, in subsequent feature games, only the reelscorresponding to symbol positions where a configurable symbol has notbeen displayed are re-spun. Each configurable symbol is assigned a valueby value assigner by randomly selecting a prize value from a set ofprize values. The set of prize values from which values are selecteddepends on the player's wager in the base game. As in the example,described above, a player is awarded the sum of the values of theconfigurable symbols at the end of the feature games and may be awardedan additional prize such as a jackpot prize depending on what value thecounter reaches during the feature games.

In another example, the configurable symbol may have an alternativevisual representation, for example, a door which opens once theconfigurable symbol is displayed in a display position to reveal theassigned prize value.

As indicated above, the method may be embodied in program code. Theprogram code could be supplied in a number of ways, for example on atangible computer readable storage medium, such as a disc or a memorydevice, e.g. an EEPROM, (for example, that could replace part of memory103) or as a data signal (for example, by transmitting it from aserver). Further, different parts of the program code can be executed bydifferent devices, for example in a client server relationship. Personsskilled in the art, will appreciate that program code provides a seriesof instructions executable by the processor.

It is to be understood that, if any prior art is referred to herein,such reference does not constitute an admission that the prior art formsa part of the common general knowledge in the art in any country.

In the claims which follow and in the preceding description of theinvention, except where the context requires otherwise due to expresslanguage or necessary implication, the word “comprise” or variationssuch as “comprises” or “comprising” is used in an inclusive sense, i.e.to specify the presence of the stated features but not to preclude thepresence or addition of further features in various embodiments of theinvention.

1. A gaming machine comprising: a housing; a display supported by thehousing, and having a plurality of display positions configured todisplay symbols; a credit input mechanism configured to receive aphysical item to establish a credit balance based, at least in part, ona monetary value associated with the physical item, the credit balancebeing increasable and decreasable based at least on a wagering activity;a memory device configured to store data indicative of 1) a first set ofsymbols, the first set of symbols including a plurality of firstsymbols, a plurality of second symbols, and a plurality of thirdsymbols, and 2) a second set of replacement symbols that also includes afirst symbol; a symbol selector configured to select a plurality ofsymbols from the first set of symbols for display on the display duringplay of a game in response to the established credit balance, to displaythe selected plurality of symbols, and to select a replacement symbolfrom the second set of replacement symbols to replace a selected thirdsymbol from the display in response to the third symbol being selected;a value assigner configured to randomly assign a prize value to aselected first symbol, including a first symbol that replaces a thirdsymbol; and an outcome evaluator configured to monitor play of the gameto determine if the selected plurality of symbols include a definednumber of first symbols, and to trigger a feature game in response tothe selected plurality symbols including a defined number of firstsymbols; wherein, during play of the feature game, the symbol selectoris further configured to: 1) cause the display to display a retaining ofat least one of the selected first symbols; 2) cause the display todisplay a removing of at least one of the selected second symbols fromthe display; and 3) cause the display to replace the removed secondsymbol with another symbol; and a payout mechanism configured to, inresponse to receiving a payout input, cause an initiation of a payoutassociated with the credit balance.
 2. A gaming machine according toclaim 1, wherein each of the first symbols comprises at least a commoncomponent and a variable component, said variable component beingindicative of a value of a prize that is associated with a respectivefirst symbol.
 3. A gaming machine according to claim 2, wherein thevalue assigner is further configured to select one of a plurality ofdefined multipliers based on an amount of a wager, and to generate avalue of the prize based on the selected one of a plurality of definedmultipliers.
 4. A gaming machine according to claim 3, wherein the valueassigner is further configured to randomly select one of the pluralityof defined multipliers with a weighted probability based at least inpart on the amount of the wager.
 5. A gaming machine according to claim2, wherein at least one of said values of the prizes comprises a definedvalue.
 6. A gaming machine according to claim 2, wherein at least one ofsaid values of the respective prizes comprises a progressive value whichincreases for each wager that is placed on the game by an amountproportional to said wager.
 7. A gaming machine according to claim 1,further comprising a first symbol counter configured to count a numberof said first symbols selected for display.
 8. A gaming machineaccording to claim 7, wherein the game is a free game of a series offree games triggered in response to a trigger event in a base game, thetrigger event comprising a defined number of a defined symbol beingselected in the base game, and when the feature game is triggered, thefirst symbol counter is initiated to count the number of selected firstsymbols in the trigger event.
 9. A gaming machine according to claim 8,wherein the first symbol counter is incremented each time a first symbolis selected for display in the feature game.
 10. A gaming machineaccording to claim 9, wherein a jackpot is awarded when the first symbolcounter has counted a defined number of first symbols, the jackpot beinga progressive prize that receives funding contributions from a pluralityof other gaming machines.
 11. A gaming machine according to claim 8,comprising a feature games counter configured to count a number offeature games to be awarded in the feature game, wherein a definednumber of feature games is initially awarded when the feature game istriggered.
 12. A gaming machine according to claim 11, wherein thefeature game counter is reset to the defined number of feature gamesinitially awarded each time a first symbol is selected for display inthe feature game.
 13. A gaming machine according to claim 11, whereinthe feature game counter is decremented each time no first symbols areselected for display in the feature game.
 14. A gaming machine accordingto claim 1, further comprising an outcome evaluator configured toevaluate the outcome of the game and to award an accumulated prize basedon said outcome, wherein the value of said accumulated prize iscalculated by accumulating the respective prizes associated with each ofthe first symbols selected for display.
 15. A gaming machine accordingto claim 1, wherein the memory device is further configured to storedata indicative of a third set of feature game symbols.
 16. A gamingmachine according to claim 15, wherein the third set of feature gamesymbols includes a first symbol.
 17. An electronic method of gaming on agaming machine having a housing, a display supported by the housing, thedisplay having a plurality of display positions configured to displaysymbols, a credit input mechanism configured to receive a physical itemto establish a credit balance based, at least in part, on a monetaryvalue associated with the physical item, the credit balance beingincreasable and decreasable based at least on a wagering activity,memory device configured to store data indicative of 1) a first set ofsymbols, the first set of symbols including a plurality of firstsymbols, a plurality of second symbols, and a plurality of thirdsymbols, and 2) a second set of replacement symbols that also includes afirst symbol, a game controller, and a payout mechanism configured to,in response to receiving a payout input, cause an initiation of a payoutassociated with the credit balance, the method comprising: establishinga credit balance via said credit input mechanism receiving the physicalitem; selecting, in accord with the established credit balance, via thegame controller, a plurality of symbols from the first set of symbolsfor display on the display during play of a game, causing, via the gamecontroller, the display to display the selected plurality of symbols,and selecting, via the game controller, a replacement symbol from theset of replacement symbols to replace a third symbol in response to thethird symbol being selected; randomly assigning, via the gamecontroller, a prize value to a selected first symbol, including a firstsymbol that replaces a third symbol; monitoring, via the gamecontroller, play of the game to determine if the selected plurality ofsymbols include a defined number of first symbols; triggering, via thegame controller, a feature game in response to the selected pluralitysymbols including a defined number of first symbols; and during play ofthe feature game, 1) causing, via the game controller, the display todisplay a retaining of at least one of the selected first symbols; 2)causing, via the game controller, the display to display a removing ofat least one of the selected second symbols from the display; and 3)causing, via the game controller, the display to replace the removedsecond symbol with another symbol; and causing, via the game controller,the payout mechanism to, in response to receiving a payout input,initiate a payout associated with the credit balance.
 18. A methodaccording to claim 17, wherein each of the first symbols comprises atleast a common component and a variable component, said variablecomponent being indicative of a value of a prize that is associated witha respective first symbol.
 19. A method according to claim 18, furthercomprising selecting via the game controller one of a plurality ofdefined multipliers based on an amount of a wager placed on the gamefrom which the feature game is triggered, and generating a value of theprize based on the selected one of a plurality of defined multipliers.20. A method according to claim 19, further comprising randomlyselecting one of the plurality of defined multipliers with a weightedprobability based at least in part on the amount of the wager.
 21. Amethod according to claim 18, wherein at least one of said values of theprizes comprises a defined value.
 22. A method according to claim 18,wherein at least one of said values of the respective prizes comprises aprogressive value which increases for each wager that is placed on thebase game by an amount proportional to said wager.
 23. A methodaccording to claim 17, further comprising counting a number of saidfirst symbols selected for display in a base game.
 24. A methodaccording to claim 23, wherein the game is a free game of a series offree games triggered in response to a trigger event in a base game, thetrigger event comprising a defined number of a defined symbol beingselected in the base game, and when the feature game is triggered, themethod further comprising initiating a first symbol counter to count thenumber of selected first symbols in the trigger event.
 25. A methodaccording to claim 24, further comprising incrementing the first symbolcounter each time a first symbol is selected for display in the featuregame.
 26. A method according to claim 25, further comprising awarding ajackpot in response to the first symbol counter having counted a definednumber of first symbols, the jackpot being a progressive prize thatreceives funding contributions from a plurality of other gamingmachines.
 27. A method according to claim 24, further comprisingcounting with a feature game counter a number of feature games to beawarded in the feature game, and awarding a defined number of featuregames when the feature game is initially triggered.
 28. A methodaccording to claim 27, further comprising resetting the feature gamecounter to the defined number of feature games initially awarded eachtime a first symbol is selected for display in the feature game.
 29. Amethod according to claim 27, further comprising decrementing thefeature game counter each time no first symbols are selected for displayin the feature game.
 30. A method according to claims 17, furthercomprising evaluating the outcome of the feature game and awarding anaccumulated prize based on said outcome, and calculating the value ofsaid accumulated prize including accumulating the respective prizesassociated with each of the first symbols selected for display.
 31. Amethod according to claim 17, further comprising storing in the memorydevice data indicative of a third set of feature game symbols.
 32. Amethod according to claim 31, wherein the third set of feature gamesymbols includes a first symbol.